Process of manufacturing barium and strontium compounds.



A. W. EKSTROM. PROCRss ON MANUFACTURING BARIUM AND STRONTIUM COMPOUNDS. APPLICATION FILED AUG.7, 1911. l1,O6759 Patented July 15, 1913.

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PROCESS OF MANUFACTURING BARIUM AND STRONTIUM COMPOUNDS.

Specification of Letters Patent.

Application filed August 7, 1911.

Patented July 15,1913. serial No. 642,791.

To 7/ tc/iom 2'1 may concern:

lie itl known that I, ARvID WV. EKSTROM, a citizen of Sweden. residing at Los Angeles, in the couutjvv of Les Angeles and State of California. have invented new and useful Tmprovements in Processes of l\/lanufacturing Barium and Strontium Compounds. of which the following is a specification.

rlhis invention relates to improvements in the manufacture of barium and strontium compounds and the principal object of the invention is the production of barium and strontium compounds by a purely chemical process. using the native salts and in conuection therewith. oil in a gaseous condition as a reducing agent. The process is adapt ed for use in connection with the native barium and strontium salts. it being the purpose to produce therefrom barium and strontiuu't sultid. carbonate, oxid, and h vdroxid.

In order to illustrate' the invention the method employed in the nuinufacturing of barium oxid or hydroxid from native barium sulfate (BaSOJ). (that is heavy spar or baryte.) will be sct forth as au eX- ample of the improved process forming the subject matter of the said invention. The said process may be set forth with the fcllowing steps: l

A. Reduction 0f bar/'um sulfate-"The baryte or heavy spar is ground to a propel' tineness, after which it is put into a closed vessel such as an earthenwarc muttle. where it is subjected to heat of a sufli 'iently high degree to cause low redness, (about 500 C.) The retort is then sealed so as to be air tight in any suitable manner. An oil spray .is injected therein above the compounds so as to form oil-gas within thev mutle, the gas passing slowly over the red hot mass not the baryte. The oil-gas, which contains hydro-carbons in differing proportions, acts as a reducer of the sulfate which is thus converted into a suld, While at the same time gases of carbon-dioxid, carbon monoxid and water, according to the circumstances. are evolved, and the gases escape through an outlet or opening and may be ignited underneath the, vessel thus utilizing their calorific energy by a perfect combustion.

The reaction that takes place may be understood by the following chemical equations:

BaS -t- 2G02 -l- WZHH; or

The reduction of the baryte sulfate just described is best carried out in a furnace mechanism like that shown in the accompan ving drawing and the process will be described with relation to the said drawing in order to more fully set forth the invention.

ln the accompanying drawing forming a part of this specification, Figure l is a longitudinal vertical sectional view through a furnace such as is preferably employed in reducing the barium and strontium compounds. Fig. Q is a transverse sectional view through the same, taken on the line 2 2 of Fig. 1. Fig. 3 is an enlarged detail sectional vicw through a portion of one of the walls of the furnace showing the ducts and passages for delivering the gas generated in the furnace to the burners thereof.

The details of the furnace mechanism will now be described, reference being had to said drawing in which 3 and 4 indicate muffles or retorts preferably formed of earthenware, and said mutl'les are mounted in a furnace structure 5 the walls thereof being made of any usual or suitable material. The muttles are located upon transverse grids 6 and 7 mounted in the furnace 5 in such a manner that spaces for the products of coinbustion may pass u wardly around and between the said Inu es and thence outwardly through any suitable outlet flue or stack S.

A space is left below the muttles to form a combustion chamber 9 into which a burner 10 or other heating means is extended through an aperture 11 in one of the walls of the furnace. The mutlies are formed open at one end. the said open end projecting through the. Walls of the furnace 5 and being adapted to be tightly closed by doors 12 and 13.

When the mufties are to be closed the doors are. put in place and are then tightly sealed. lhe door 12 of the upper mutlle is provided witha spraying nozzle 14 of any desired type for introducing oil or other materials iu sprayed form into said muille. I have found it highly desirable in previous experiments to inject the oil sprayed from the nozzle above the charge, as the solid carbon residue which naturally settles on the same will become rapidly oxidized by the Habit), and converted into a gaseous carbon monoxid and carbon dioxid, thus eliminating any danger of clogging the mntlie. 'lhis method of spraying above the charge has also been found desirable in case a perforated tray is used, for, by spraying beneath the tray the perforations would quickly become clogged rendering the process inoperative in a short period. The said door12 is also provided with an aperture 15 adapted to berlosed by any slide or plate 16. The door affords a means for introducing rakes or other implements into the mutile for distributing and moving the materials therein treated. The lower door 13 is provided with a similar opening 17 adapted to be closed by a slide or plate 18 and affording access to the interior of the lower muffles.

The two mufiles are connected by a vertical chute 19 which is made to extend almost the entire width of the mutiies but may be narrower in cross section as shown in Fig. 1. The passage formed in said chute 19 is made with downwardly flaring walls so that the materials passing through the same cannot become clogged therein. The upper inutile is charged b r means of a hopper 20 mounted upon the top of the furnace and 'communicating with the said inutile by lneans of a connecting passage 21 formed in the top of the furnace and an aperture 22 in the top wall of the inutile. A valve 23 adapted to tit in the outlet of the hopper and controlled by a hand lever 2J. is employed to regulate the admission of material to be treated into the said upper inutile.

The chute 19 is located near the inner ends of the mulles so that the materials treated in the upper mutlle may be p'ushed into the passage in said chute and allowed to fall into the loweemule where it is again subjccted to the hotgases evolved from the upper inutile. At a later period of the operatio-n the material in the' lower muiile is discharged through a similar downwardly flaring chute 25 formed in the wall of the furnace 5. The lower end of the said chute 25 communicates with a broad fiat pipe or chute 26 so that the treated materials may be, led from the lower muiiie into a receptacle or tank 27 which normally contains water, the said pipe 26 extending into the water and below the surface thereof. The walls of the furnace are also provided with gas duets 2S and 2S) in the side walls thereof as clearly shown in Figs. 1 and 2, the said ducts communicating with the chute 23 b v means of small passages 30 with slots 31 formed in the walls of the combustion chamber 9. There are preferably a number of said slots extending along each side wall of the combustion chamber, and the gases generated in treating the barium or strontium compounds will be conducted by the chute 25 and the ducts 2S to the said slots 31 where the gas escapes into the combustion chamber of the furnace and becomes ignited for beating the same.

Sliding valves 32 are mountedin passages 33 formed in the walls of the furnace?) and adapted to control the gas passages 30. Operating handles 34 extend from said sliding valves to the exterior of the furnace.

The tank 27 is provided with a draw ol' pipe 35 controlled by a Valve 36 and having a strainer 37 upon its inner end through which the materials deposited from the muftles and taken up in solution in said tank 27 may be withdrawn therefrom. A valve controlled pipe 3S also extends into the lower part of the said tank 27 for introducing steam Vthereto and maintaining water at proper temperature.

In using the furnace the process is carried out in the following manner: The compounds to be treated are placed in the hopper 20 and suitable charges thereof are introduced into the upper muiiie 6 by operating the valve 23. The materials are then spread out in a layer upon the bottom of the inutile to a thickness of say from three to four inches. The materials are reached through the door 15 so that they may be spread by rakes, hooks or other implements. After this is done the temperature in the furnace. is raised to red heat so as to bring the materials to the point of reduction and the air of the muiles is expelled there from by means of any7 suitable steam jet. The cil is then introduced in the form of a spray from the nozzle 14 above the charge therein and usually yunder suitable pressure to form Va finely divided spray. When the oil thus sprayed comes in contact with the heated charge or the walls of the maille it will im mediately be gasitied and will tend to reduce the charge and then pass out. through the chute 19 to the lower muiiie 7 Where it will further reduce a preceding charge which has been delivered into a. second mutlle beneath.

The charge is usually allowed to remain in the upper mufe 6 for about an hour, at the end of which time it is caused to drop through the chute 19 to the lower mattie 7 where it is again Spread into a suitable layer by means of implements inserted through the door 17. A new charge is also introduced at this time into the upper muflie 6 as above described. In the lower -Inutile 7 the Vcharge is allowed to remain about two hours at the end of which time it is discharged through the outlet chute Q5 passing thence through the pipe 2o into the tank 2T. During all this time oil is allowed to iiow for treating the charge and forming the gas and when the openings 15 and 17 are uncovered to move or spread the charges of the milities, the gases within having a slight pressure due to their generation, have a tendency to shoot out. of said aperturesl thus preventing the air entirely from enteringl the inutiles and coming in contact with the materials therein, which at the temperature maintained within the muflle is oxidized very easily. The charge in passing from the pipe 2o into the tank'QY is admitted thereto below the Vater level so that air cannot enter the ports ot' the furnace or the inutiles for oxidizing any of the contents thereof. Tt will he noticed in this process that the oxidation due to the presence of air is fully guarded against from the time the materials enter the upper muHie until leaving the dissolving tank Q7 as sultid.

The upper inutile G serves for the complete gasification of the oil and also heating of the gas formed therein, for the preheatiug of the new charge. and partially for the reduction of the same. The lower niutiie is'adapted for the complete reduction of the charge which was previously treated in the upper inutile, it being found to be capable of reducing fully 95% of the charge. The lower Inutile is arranged in the furnace described as closely to the source of heat. as is compatible With an even distribution of the heat so that the temperature of the same is consequently somewhat higher than that of the upper mutlie and thus facilitating the final reduction. Occasionally the charges are stirred by means of stirring hooks in order to facilitate the reaction.

The structure of the furnace is such that when the temperature has been raised to the proper degree the oil burner 10 may be gradually shut down and simultaneously more, oil is introduced through the nozzle 14 and into the upper mutiie 6 producing a greater quantity of combustible gases Within the inutile.

Then the process has progressed so that the temperature of the muttles has been raised to the proper degree the oil burner 10 maiY be entirely shut ott' and the oil sprayed from the nozzle 14 above the charge will supply a sutiicient amount of oil to produce the gas necessary for the reduction of the charge and for the maintenance of the proper temperature in the furnace, the combustible gases from the inutiles being burned as they escape from the opening 31 in the combustion chamber.

Then the charge in the lower muiie has been treated for a suitable length of time, it is so raked as to fall in a red hot condition through the chute 25 and the pipe 9,6 into the Water contained in the tank 2T. The water in said tank is at the same time maintained at a temperature, of about 80 centigrade by means of steam which is injected through the pipe 38 thereby aiding the dissolving of the suliid, when the mass has thus been lixiviated, thel solution, which, besides the sulfid produced by they treating of the charges, also contains some suspended matter consisting of unreduced sulfate and free carbon, (from the oil) is drawn oft' through the pipe 35 and conducted to any suitable apparatus for claritication.

In the clarifying apparatus the mechanically suspended impurities of thesolution can be easily separated and dried for further use in the first step of the process and the sultid solution may beconducted to any suitable apparatus for the earbonating of the barium sultid.

It will be understood that in place of the oil spray delivered at the nozzle 14, an oilsteam-spray or oil-prodin-er-gas or natural gas may be injected into the. upper inutile, for providing a reducing agent within the same without departing from the spirit of the invention.

The next step of the process is as follows:

I?. aronating of barium,- suZ 77'(Z.-l`he barium sultid (BaS) obtained as described above is` when dissolved in hot water, hydrolyzed and converted into barium sulfhydrate lBa(SH)2] and barium hydro-xid [BMOHL] the chemical reaction being:

eBasJfeHgozBMsH) Lea (on Through this solution a current of carbon dioxid (CO2) is passed in order to desulfurize the same. The barium held in solution is thus precipitated as barium carbonate (BaC1/os) and the sulfur in the state of gaseous sulfureted hydrogen (H28) is expelled from the solution. The chemical reaction that takes place is as follows:

absorbed by the solution and converted into' carbonate. When the percentage of alkalinity of the liquid has become decreased to uucarbonated snltid in solution.

about 0.3% it is preferable to discontinue the current of carbon dioxid as it is very dillicnlt to convert the balance of the sultid into carbonate. The tanks are usually so arranged that any of them maybe disconnected from the system by means of valves.

During the carbonating process the solution should bc kept at about 90o centrigrade, this temperature being the most advantageous toi-'the absorption of the carbon dioxid. and in order to maintain such a tcmperature a stream of steam may be injected into the solution. The carbonate rapidly setties on the bottom ot' the tank and after some time the solution is dccanted androndncted to the lixiviat ion-tanks to be subsequently used for dissolving another quant-ity ot sultid, thereby avoiding the loss ot any remaining After having carefully Washed the carbonate with wa ter, the liquid is discharged from the tank and the carbonate dried in any suitable apparatus.

T he sulinrcted hydrogencvolved through the reaction may be led otl and treated in the usual manner :For the removal of the obnoxious odors aud for the recovery of the sulfur.

Dcmrnmating of i710 horiz/m.. ff/:17m11- rhn---Jfhe barium carl'mnatc (BaCOQ thus obtained is put into the upper mullle of a furnace' like that described in carrying ont step A. It is yneicrable however in this instance to employ magnesia muliles as the barium oxid at red heat has a strongly corrosive ell'ect on silicious or aluminous material. rlhe operation should be carried out in exactly the saine manner as described in step A for reducing the sulfate. rlhe barium carbonate after having been heated to a red heat (or about. 5G00 to 600 ccntigrade) is treated with oil sprayed' into the mullie whereby the carbonate Will be converted into barium oxid (BaO) and this product is then dissolved in water in the same manner described ivith respect to the suliid, for obtaining barium hydroxid [Ba(OH)2], the reaction that takes place in reducing the carbonate may be expressed in the followingr equations:

BaCO-{-C,II (hydrocarbon):

The reduction of barium carbonate is highly facilitated by an admixture of lime or chalk, a ratio by Weight, of two parts of barium carbonate to one of lime being advantageously employed. A charge of this character will neither frit nor stick to the bot-tom of the muttle during the operation but instead will remain porous and thus very permeable to the reducing gases.

W'hile the barium oxidpeasily` dissolves in Water forming hydroxid, the lime remains practically insoluble and after separation from the'solution it may be dried and used over again.

It will be understood that strontium sultid, carbonate, oxid, and hydroxid may be obtained from the native strontium compounds in the same manner, and by the same treatment as that above set forth in the treatment of barium. i

What I claim. is:

The process of reducing barium and strontium compounds Without previously mixing therewith carbonaceous materials, which consists in subjecting said compounds to heat in a suitable receptacle in the presence of hydrocarbon gases generated from oil injected therein above said compounds, air bcing excluded from said receptacle.

In witness that I claim the foregoing I have hereunto subscribed my name this 15th day ot' July, 1911.

ARVID W. EKSTROM.

Titnesses E. STADTMAN 7 EARLE R. POLLARD. 

